The present invention relates to a tape system that can include a tape drive and a tape cartridge for housing data storage tape and, in particular, to a tape drive that includes a control mechanism for attaching/detaching at least one leader band to/from the data storage tape.
Tape drives having a single tape reel use removable tape cartridges for obtaining the tape upon which and from which such tape drives write/read data. In particular, each of the tape cartridges used by such a tape drive has a complementary tape reel therein upon which the tape resides when not being operatively used in conjunction with the tape drive. In order to protect the tape and the data thereon from damage, the tape within each cartridge is not intended to be accessible except by the tape drive. Accordingly, the tape drive must include a mechanism for automatically threading the tape through the tape drive between the tape cartridge and the single reel of the tape drive. Various techniques have been used to perform such automatic threading. In connection with designing such tape drives, certain technical challenges have been identified that are commonly addressed, namely:
(a) The mechanism for pulling the tape through the tape drive is frequently unreliable in that, e.g., the tape drive threading components used for engaging with the free end of the tape during the threading of the tape by the tape drive do not engage reliably. Similarly, the tape drive components may also fail to disengage from the tape during the unthreading of the tape from the tape drive. Thus, the tape drive may fail to access the tape in some cartridges and/or a tape cartridge may become stuck within the tape drive.
(b) Once the free end of the tape has been secured for threading to, e.g., what is known in the art as a xe2x80x9cleader bandxe2x80x9d (or simply xe2x80x9cleaderxe2x80x9d), the tape free end may inadvertently disengage from the leader band during threading and/or become misaligned and fail to fully thread thus potentially damaging the tape drive.
(c) Due to the flexibility and thinness of many tapes currently used for data storage, the free end of the tape itself is not typically grasped (ungrasped) during threading (unthreading) operations. Instead, an appendage is provided on the free end of the tape, wherein this appendage is more readily grasped (ungrasped). Such an appendage may include a substantially rigid cylindrical, semicircular or other shaped component having a thickness substantially greater than the thickness of the tape. Alternatively, the appendage may include a slot for mating with an end portion of the leader band. In all such cases, the resulting coupling of the tape free end and the leader band is substantially thicker than the tape itself. Thus, when this substantially thicker coupling portion winds about the single reel of the tape drive, a non-smooth surface results which can compromise the data encoded on the tape that is subsequently wound on top of the non-smooth surface.
Although solutions to these technical issues have been advanced, it remains desirable to provide a tape drive that overcomes or alleviates them in an efficient manner. Such solutions should avoid complex mechanical configurations, be cost effective and reliable.
In accordance with the present invention, a tape system is provided that includes a take up assembly for winding/unwinding magnetic or other data storage tape. The tape system also includes a leader assembly to which the data storage tape is releasably joined. The tape system further includes a load/unload control mechanism that functions to attach/detach the leader assembly to/from the tape.
The load/unload control mechanism engages at least portions of the leader assembly to cause desired movement thereof in conjunction with tape loading/unloading relative to the removably held tape cartridge. In that regard, the control mechanism is used in moving the leader assembly in at least two directions when loading or joining the leader assembly to the storage tape. In one embodiment, the control mechanism causes the portions of the leader assembly to move in a first direction that is generally a straight movement from the tape drive to the tape cartridge. And, a pivotal movement is then caused to occur, preferably in a clockwise direction, for positioning the leader assembly to engage the storage tape. More specifically, the storage tape has a pin held adjacent to its free end. The leader assembly includes at least a first leader band and a connector subassembly. In one embodiment, the leader assembly has first and second leader bands. The connector subassembly can include a pair of hooks interconnected by a hook stay. In this embodiment, when loading the data storage tape, the control mechanism causes upper portions of at least the first leader band and the hook subassembly to move into the tape cartridge and then pivot clockwise. When necessary or desired, the hook subassembly and the upper portions of the at least first leader band are then moved in a substantially straight direction towards the exit of the tape cartridge. In so doing, the hooks engage the tape pin and remove it from its seat as the hook subassembly and the upper portions of the first leader band move to exit the tape cartridge.
Comparable opposite directional movements are caused to occur when the storage tape is detached from the leader assembly (unloading operation). In particular, the leader assembly holding the tape pin moves into the tape cartridge and continues in a generally linear direction. During this movement, the tape pin seat for holding the tape pin in the tape cartridge is encountered. After the tape pin seat receives the tape pin, the hook subassembly and upper portions of the first leader band are caused to move in a counterclockwise direction. Alternatively, if desired or appropriate, after release of the tape pin in the tape pin seat, the leader assembly may continue for a short distance in the generally straight direction and then pivot counterclockwise. After the counterclockwise movement, the leader assembly is caused to move without the tape pin in the opposite generally linear direction towards and out of the tape cartridge.
The control mechanism for causing such loading/unloading movements can include a number of gears. These gears might include a drive gear, which is attached to a shaft of a motor. The gears can also include a planetary gear that meshes with the drive gear. A sprocket gear can also be provided to rotate one or more sprockets. Such a sprocket will engage holes in the first leader band, for example. A cam gear may also be utilized for use in rotating a cam. The cam movement is useful in causing the pivoting movement of the hook subassembly.
The planetary gear is selectively meshable with either the sprocket gear or the cam gear. When moving the leader assembly in the generally linear directions, the planetary gear meshes with the sprocket gear, and not the cam gear, so that when the planetary gear is driven, the sprocket gear causes the one or more sprockets to move the leader assembly in the generally linear directions. When a planetary gear meshes with the cam gear, and not the sprocket gear, the cam is caused to rotate to achieve the selected rotational or pivotal movement.
With regard to achieving the selective engagements between the planetary gear and the sprocket gear and between the planetary gear and the cam gear, the control mechanism can include a pivotal arm. When the motor is driven clockwise, the pivotal arm rotates clockwise. When the motor is driven counterclockwise, the arm rotates counterclockwise. When the arm rotates clockwise, it disengages the planetary gear from the sprocket gear and engages with the cam gear. When the arm rotates counterclockwise, the planetary gear is disengaged from the cam bear and engaged with the sprocket gear.
The control mechanism preferably also includes a biasing device, such as a spring. The spring is operably connected to other portions of the control mechanism. The spring is preferably biased to allow or enable at least portions of the control mechanism to pivot in a counterclockwise direction. Consequently, when the leader assembly is caused to pivot in the clockwise direction, the force of the spring must be overcome during such pivotal movement.
Although the control mechanism can be used with any number of different configurations, in a preferred embodiment, the take up assembly includes a take up reel hub having at least a first take up reel connected to and spaced from the take up reel hub. In an even more preferred embodiment, first and second take up reels are provided, with the take up reel hub located intermediate thereof. The take up reel hub has a circumferential surface about which the magnetic tape winds and unwinds. Each of the one or both take up reels has a leader band wound thereabout. Because of the spaced, separate take up reel or reels, there is no overlap or contact between the leader bands and the magnetic tape.
Based on the foregoing summary, a number of advantages of the present invention are readily discerned. A reliable tape loading/unloading control mechanism is provided. The control mechanism causes different movements in order to enter the tape cartridge and either access or release a tape pin. A reduced number and efficient use of parts are achieved in the control mechanism design. In that regard, a unique arrangement and operation of a number of driven gears and a cam are provided. The control mechanism controls desired movement of both an elongated storage tape and a connector subassembly, in the form of a pair of hooks, into and out of a tape cartridge. In one embodiment, the leader assembly with which the control mechanism functions has first and second leader bands spaced from but connected to each other using the hook subassembly. In another or the same embodiment, the take up assembly has separate parts for winding/unwinding the storage tape and winding/unwinding one or more leader bands.
Additional advantages of the present invention will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings.